Abstract
Background:
Quail (Coturnix coturnix Japonica) is becoming an increasingly important source of meat and eggs worldwide. Some management and environmental issues are restraining the enhancement of quail farming.

Aim:
This study examined the growth performance of Japanese quail as influenced by feeding regimens and dietary supplementation with Spirulina platensis (SP).

Methods:
A total of 324 Japanese quail chicks [1-week old; initial body weight (BW): 34.5 g] were haphazardly divided into 12 groups (27 birds/group), with each group had three replicates (nine chicks/each), involving four feeding regimens [ad libitum (ADLIB), feeding on 85% of the requirements (85REQ), ADLIB within 16 hours/day (ADLIB16), 85REQ within 16 hours/day (85REQ16)], and three levels of dietary SP (0%, 0.5%, and 1%).

Results:
BW at marketing and BW gain at different ages were influenced by the feeding regimen. Birds that consumed 85REQ16 showed the lowest feed consumption (FC) at 1–3 weeks of age. During 4–6 and 1–6 weeks of age, quails fed on 85REQ and those fed on 85REQ16 consumed less feed. Quails of 85REQ16 exhibited the highest carcass, dressing, and giblet weights. Dressing and giblet weight differed due to the interaction between feeding regimen and dietary SP. Blood biochemicals were impacted by the feeding regimen, except for glucose concentration. Total protein, albumin, and globulin levels were low in 85REQ-fed quails. Quails fed a 1% SP-supplemented diet showed the lowest level of cholesterol and the greatest level of total antioxidant capacity. Most of the blood biochemicals studied fluctuated because of the interaction between the feeding regimen and dietary SP. The Lactobacillus count was the highest among the treatments as affected by the feeding regimen. Lactobacillus and Enterococcus counts increased with increasing dietary SP, whereas the reverse was observed in Salmonella and Staphylococcus counts. Birds fed SP0.0 with 85REQ16 and those fed SP0.0 with 85REQ had the highest (128.52 and 126.68%; respectively).

Conclusion:
In conclusion, quail could be kept under a feed regimen of 85REQ16, with dietary supplementation of SP for healthier growth performance.

Key words: Feed restriction, Growth, Microbial count, Japanese quail, Spirulina platensis